The submental triangle (or suprahyoid triangle) is a division of the anterior triangle of the neck.Muscles of the neck. Anterior view.The veins of the neck, viewed from in front.Front view of neck.The triangles of the neck. (Anterior triangles to the left; posterior triangles to the right. Suprahyoid labeled at left.) The submental triangle (or suprahyoid triangle) is a division of the anterior triangle of the neck.